WebRTC[14]-WebRTC如何通过参数控制编码模式切换（DIsabled模式）

webrtc::DegradationPreference
WebRtcVideoChannel::WebRtcVideoSendStream::GetDegradationPreference() const { // Do not adapt resolution for screen content as this will likely // result in blurry and unreadable text. // |this| acts like a VideoSource to make sure SinkWants are handled on the // correct thread. webrtc::DegradationPreference degradation_preference; if (rtp_parameters_.degradation_preference !=
      webrtc::DegradationPreference::BALANCED) { // If the degradationPreference is different from the default value, assume // it is what we want, regardless of trials or other internal settings. degradation_preference = rtp_parameters_.degradation_preference;
  } else if (!enable_cpu_overuse_detection_) {
    degradation_preference = webrtc::DegradationPreference::DISABLED;
  } else if (parameters_.options.is_screencast.value_or(false)) {
    degradation_preference = webrtc::DegradationPreference::MAINTAIN_RESOLUTION;
  } else if (webrtc::field_trial::IsEnabled( "WebRTC-Video-BalancedDegradation")) {
    degradation_preference = webrtc::DegradationPreference::BALANCED;
  } else { // TODO(orphis): The default should be BALANCED as the standard mandates. // Right now, there is no way to   degradation_preference = webrtc::DegradationPreference::MAINTAIN_FRAMERATE;
  }  degradation_preference;
}